Method for reducing condenser size and power on a heat rejection system

ABSTRACT

A heat transfer system for high transient heat loads includes a fluid, a heat exchanger; a compressor downstream of the heat exchanger outlet; a condenser downstream of the compressor outlet, and a thermal energy storage (TES) section downstream of the condenser outlet and upstream of the heat exchanger. The TES section may include a first pressure regulating valve downstream of a TES unit; and a second pressure regulating valve upstream of the first pressure regulating valve.

CROSS REFERENCE TO RELATED APPLICATION

This application is related to concurrently filed and co-pending U.S.application Ser. No. ______, titled “Method for Reducing Condenser Sizeand Power on a Heat Rejection System,” Docket Number:G2640-00314/LWA12293, first named inventor: Eric Donovan. Thisapplication is also related to concurrently filed and co-pending U.S.patent application Ser. No. ______, titled “Mechanically Pumped Systemfor Direct Control of Two-Phase Isothermal Evaporation”, Docket NumberG3106-00290/LWA12265, first named inventor: Eugene Jansen. The entiretyof each of these applications is incorporated herein by reference.

BACKGROUND

Conventional methods of rejecting heat from a refrigerant or coolingsystem, e.g., vapor compression systems or phase change cooling system,requires sizing the heat-rejecting component(s), e.g., the condenser andfans, for a maximum design heat load at a maximum design ambienttemperature. However, many heat loads may operate on a cycle wherein themaximum heat load occurs during only a portion of that cycle.Additionally, the maximum design ambient temperature likely is notalways present. Some heat-transfer systems employ complex,variable-frequency-drive compressors to facilitate the heat-rejectioncapacity control that are expensive and frequently operate thecompressor away from its peak efficiency. Sizing the heat exchangersystem for the maximum heat load at continuous duty cycle in the maximumexpected ambient air condition results in an oversized, overweight, andoverpowered condensing unit for those portions of the duty cycle thatare neither at, nor near, the most limiting design conditions.

SUMMARY

According to some aspects of the present disclosure, a heat transfersystem may include a primary fluid and a primary fluid flow path. Theprimary fluid may be disposed in the primary fluid flow path. Theprimary fluid flow path may include a heat exchanger with an inlet andan outlet, which transfers heat into the primary fluid; a compressor,with a compressor inlet and a compressor outlet. The compressor inletmay be downstream of and coupled to the heat exchanger outlet by aheat-exchanger-compressor conduit. The flow path may include acondenser, with a condenser inlet and a condenser outlet. The condenserinlet may be downstream of and coupled to the compressor outlet by acompressor-condenser conduit. The condenser may transfer heat out of theprimary fluid. The flow path may also include a thermal energy storage(TES) section. The TES section may include an inlet and an outlet. TheTES section inlet may be downstream of and coupled to the condenseroutlet by a condenser-TES-section conduit. The TES-section outlet may beupstream of and coupled to the heat exchanger inlet by aTES-section-heat-exchanger conduit. The TES-section may include a TESunit having an inlet and outlet. The TES unit inlet may be downstream ofand coupled to the TES section inlet by a TES-section-TES-unit-inletconduit and the TES unit outlet may be upstream of and coupled to theTES Section outlet by a TES-unit-TES-section-outlet conduit. TheTES-section may also include a first pressure regulating valvedownstream of the TES unit; and a second pressure regulating valveupstream of the first pressure regulating valve and downstream of thecondenser. The second pressure regulating valve may maintain the primaryfluid at the condenser outlet at a first state when the heat transferredinto a portion of the primary fluid by the heat exchanger may be equalto or less than the heat transferred out of the portion of the primaryfluid by the condenser. The first pressure regulating valve may maintainthe primary fluid at the TES unit outlet at the first state when theheat transferred into a portion of the primary fluid by the heatexchanger may be greater than the heat transferred out of the portion ofthe primary fluid by the condenser. The TES section may maintain theprimary fluid at the TES section outlet as a liquid-vapor mixture.

In some embodiments, the first state may be at saturation pressure. Insome embodiments, the first state may be a subcooled liquid. In someembodiments, the first state may be a saturated fluid. In someembodiments, the heat exchanger may be an evaporator. In someembodiments, the TES unit comprises a material selected from the groupconsisting of a phase change material, chilled water, chilled coolant,or two-phase mixture of water and ice. Some embodiments may include abypass valve upstream of TES unit and downstream of the condenser. Insome embodiments, the bypass valve may direct the primary fluid to thesecond pressure regulating valve in a first position or to the TES unitin a second position. Some embodiments may include a TES cooling fluidconduit coupled to the TES-section-heat-exchanger conduit and the bypassvalve, wherein the bypass valve may be a four-way valve. In someembodiments, the bypass valve may be in parallel with the secondpressure regulating valve. In some embodiments, the second pressureregulating valve maintains the primary fluid at the TES unit inlet as aliquid-vapor mixture. Same embodiments may include a first bypass valvedownstream of the TES unit and coupled in parallel with the firstpressure regulating valve; and, a second bypass valve upstream of theTES unit and coupled in parallel with the second pressure regulatingvalve. In some embodiments, the second pressure regulating valve may beupstream of the TES unit. In some embodiments, theTES-section-heat-exchanger conduit comprises an accumulator and a liquidpump, and the heat-exchanger-compressor conduit comprises theaccumulator. Some embodiments may include a TES cooling fluid conduitcoupling an outlet of the liquid pump and a four-way valve upstream ofTES unit and downstream of the condenser.

According to some aspects of the present disclosure, a heat transfersystem with a closed fluid flowpath may include in a direction of fluidflow a heat source, a compressor, a condenser, a first bypass valve in afirst mode or a first pressure regulating valve in a second mode, athermal energy storage (TES) unit, and a second pressure regulatingvalve in the first mode or a second bypass valve in the second mode. TheTES unit may be a heat sink in the first mode and the TES unit may be aheat source or heat neutral in a second mode.

In some embodiments, the first pressure regulating valve may be adiaphragm-style back pressure regulating valve. In some embodiments, atleast one of the first pressure regulating and the second pressureregulating valve may be a pneumatically controlled valve.

According to some aspects of the present disclosure, a heat transfersystem with a fluid flowpath may include in a direction of fluid flow aheat source, a compressor, a condenser, a first input of a four-wayvalve, a thermal energy storage (TES) unit in a first mode or a firstpressure regulating valve in a second mode, and a second pressureregulating valve. The TES unit may be a heat sink in the first mode andthe TES unit may be a heat source or heat neutral in a second mode.

In some embodiments, the TES unit may include a material selected fromthe group consisting of a phase change material, chilled water, chilledcoolant, or two-phase mixture of water and ice. In some embodiments, theheat source may be an evaporator. Some embodiments may include anaccumulator; and a pump. Some embodiments may include a second flow pathwhich itself may include the pump, a second input of the four-way valve,the TES unit, the second pressure regulating valve, and the accumulator.

BRIEF DESCRIPTION OF THE DRAWINGS

The following will be apparent from elements of the figures, which areprovided for illustrative purposes.

FIG. 1 is a graph of various heat loads with respect to time.

FIG. 2 illustrates a heat transfer system in accordance with someembodiments.

FIG. 3 is a graph of a heat load with respect to time.

FIG. 4 illustrates a heat transfer system in accordance with someembodiments.

FIG. 5 illustrates a heat transfer system in accordance with someembodiments.

FIG. 6 illustrates a heat transfer system in accordance with someembodiments.

FIG. 7 illustrates a heat transfer system in accordance with someembodiments.

The present application discloses illustrative (i.e., example)embodiments. The claimed inventions are not limited to the illustrativeembodiments. Therefore, many implementations of the claims will bedifferent than the illustrative embodiments. Various modifications canbe made to the claimed inventions without departing from the spirit andscope of the disclosure. The claims are intended to coverimplementations with such modifications.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thedisclosure, reference will now be made to a number of illustrativeembodiments in the drawings and specific language will be used todescribe the same.

Conventional methods of rejecting heat from a heat transfer system,e.g., a refrigerant system, requires sizing the heat-rejectingcomponent(s), e.g., a condenser, fans, etc., for a maximum designambient temperature and maximum design heat loads. Such methods may workwell for a heat load with little variation, such as heat load 101 shownin FIG. 1. Heat load 101 may be, for example, a building in which thevariation in heat load 101 is driven by daily fluctuations in ambienttemperature and building use. However, this design philosophy results inheat-rejecting components, e.g., condensers and/or fans, that may bemuch larger than what is required for average ambient temperaturesand/or average loads, particularly for systems having widely varyingand/or intermittent loads such as heat load 103. Heat load 103 may havea low, steady state heat load that is periodically interrupted by shortperiods of significantly higher heat loads. Additionally, thetemperature of cooled load, or the temperature at which the load is tobe maintained, may be different during the low, steady state heat loadand the higher heat load. A system designed to accommodate heat load 103typically would size the heat-rejecting components, like the condenser,to handle the larger, less frequent load, resulting in condenser that ismuch larger and/or fans that are required to provide significantly moreairflow (and power required to drive those fans) than what is requiredto support the lower, average load. These system designs occupy morevolume, weigh more, may require more power for transfer of cooling fluidor air, and may respond more slowly during transients.

In accordance with some embodiments, a heat transfer system 200 isillustrated in FIG. 2. The system 200 may comprise a primary fluid flowpath 202 having a primary fluid disposed therein. The primary fluid flowpath 202 may comprise various components configured to transfer the heatfrom one location and dispose of it into another. These other componentsmay comprise heat exchanger 204, compressor 206, condenser 208, andthermal energy storage (TES) section 210. These components may bearranged in a loop such that each subsequent component, as listed in theorder above, being located downstream of the prior components and theeffluent of the TES section 210 being returned to the heat exchanger 204to complete the loop.

Each of above components forming the primary fluid flow path 202 may becoupled to one another via one or more conduits. For example, the outlet260 of heat exchanger 204 may be coupled to the inlet 262 of compressor206 via the heat-exchanger-compressor conduit 264; the outlet 266 ofcompressor 206 may be coupled to the inlet 268 of condenser 208 by thecompressor-condenser conduit 270; the outlet 272 of condenser 208 may becoupled to the inlet 274 of TES section 210 by condenser-TES-sectionconduit 276; and, outlet 278 of TES section 210 may be coupled to theinlet 280 of heat exchanger 204 by a TES-section-heat-exchanger conduit282.

Primary fluid flow path 202 may comprise additional components and/orconduits, some of which are described herein. The primary fluid flowpath 202 may form a closed fluid flow path, meaning that the system 200is designed such that the primary fluid does not intentionally enter orleave the primary fluid flow path 202 during normal operation. Beingcharacterized as closed does not prohibit, however, primary fluid frombeing added to or removed from the primary fluid flow path 202 to makeup for leaks, change of the primary fluid after fluid degradation, orfor some other maintenance or repair procedure.

The primary fluid disposed with the primary fluid flow path 202 can beany appropriate fluid, vapor or liquid, capable of achieving the desiredheat transfer. For example, the primary fluid may be water or arefrigerant. The particular fluid for system 200 can be dependent uponthe heat load and the temperature of the environments/systems thattransfer heat into or out of the system 200.

Heat exchanger 204 may be of suitable type for transferring heat 212into the primary fluid, which runs in the cold-side channels (or tubesor other appropriate geometry) of heat exchanger 204. Heat exchanger 204may be a heat source or load. The hot-side channels may be filled withfluid, e.g., water or air, from the environment/system to be cooled.Heat exchanger 204 may be a parallel-flow, cross-flow, multi-pass-flow,or counter-flow heat exchanger. In some embodiments, heat exchanger 204is an evaporator that evaporates a portion or all of the primary fluidflowing therein. In some embodiments, heat exchanger 204 may comprise aseries of conduits thermally coupled to a heat source or load that isnot a fluid. For example, the conduits of heat exchanger 204 may beplaced in thermal proximity, contact, or coupling with a solid structurethat produces heat such that this heat is transferred into and removedby the primary fluid.

The heat transfer 212 into the primary fluid in heat exchanger 204 maybe a variable load such as heat load 103 as shown in FIG. 1. Anotherexample of a variable load 300 is illustrated in FIG. 3. As can be seen,heat load 300 is above its average heat load 303 for only a portion oftime. A typical heat transfer system would be sized based on the peakheat load 305. This design results in a condenser, compressor, and/orfans that are oversized for all but the peak heat load 305.

Compressor 206 raises the pressure of the primary fluid. This increasein pressure may be used to provide the workflow required to circulatethe primary fluid within the primary fluid flowpath 202. Raising thepressure of the primary fluid may also raise the temperature of theprimary fluid, thereby allowing heat to be rejected from the primaryfluid in the condenser 208. In some embodiments, compressor 206 may be apump configured to raise the pressure of liquid, such as in anabsorption system (see FIG. 7, discussed below).

Condenser 208 receives the higher-temperature/pressure primary fluidfrom the compressor 206. Condenser 208 may be a heat exchanger thatrejects heat 214 from the primary fluid to a heat sink which may be,e.g., the ambient environment. Condenser 208 may be a parallel-flow,counter-flow, multi-pass-flow, or cross-flow heat exchanger. The primaryfluid may run in the hot-side channels of condenser 208. The cold-sidechannels of condenser 208 may be filled with a fluid from the heat sink,e.g., ambient air.

Condenser 208 may be sized such that the condenser 208 may beinsufficient to condense and/or sub cool all of the primary fluidflowing therethrough when heat input 212 and compressor 206 power andheat input is sufficiently larger than heat-out 214 (a person ofordinary skill will recognize that the energy inputted into system 200must be rejected at some point in order for the system 200 to continueeffective operation; as such, heat input 212 can be considered asincluding additional sources of energy (from, e.g., pump work) even ifnot expressly stated herein). To accommodate this intermittent, maximumload, system 200 may comprise a TES section 210 to which heat may betemporarily rejected. Once the heat input 212 and compressor 206 powerand heat input drops below a particular rate relative to rate of heatoutput 214 of condenser 208, condenser 208 may condense and/or sub coolthe primary fluid. This primary fluid is then used to cool, or“recharge,” the thermal capacity of TES section 210.

With reference to FIG. 3, if the condenser 208 is sized to accommodatethe average heat load 303, a heat input above the average 303, asrepresented by heat-excess area 307, will prevent the condenser fromcondensing and/or sub cooling the primary fluid. During this period, thesupplemental heat capacity of TES section 210 is used to make up for thedeficiency of the condenser 208. When the heat load 300 is less than theaverage heat load 303, as represented by the area 309 in FIG. 3, thecondenser 208 has capacity to condense and/or sub cool a portion or allof the primary fluid that may be subsequently used to recharge the TESsection 210 (and, in particular, the TES unit 220 as described below)while concurrently rejecting the heat from heat load 212.

In some embodiments, condenser 208 may comprise a force ventilation unit(not shown), such as a fan, that increases the flow rate of the ambientenvironment fluid over condenser 208. The “sizing” of the condenser 208may factor in the addition of the forced ventilation unit.

To provide this thermal capacity, TES section 210 may comprise severalcomponents, including pressure regulating valve 216, bypass valve 218,TES unit 220, pressure regulating valve 222, and bypass valve 224.

TES unit 220 has an inlet 226 and outlet 228. Inlet 226 of TES unit 220is downstream of and coupled to TES section inlet 274 byTES-section-TES-unit-inlet conduit 284. Outlet 228 of TES unit 220 isupstream of and coupled to TES section outlet 278 byTES-section-TES-unit-outlet conduit 286. As shown in FIG. 2 and otherfigures, the conduits coupling the TES unit 220 to the inlet and/oroutlet of the TES section 210 may have various components disposedtherein and/or coupled in parallel with all or a portion of theconduits.

TES unit 220 provides a secondary heat sink for the primary fluiddisposed in the primary fluid flow path 202. When the heat input 212from heat exchanger 204 and compressor 206 power and heat input issufficiently large such that the heat output 214 of condenser 208 cannotfully condense the primary fluid within the condenser 208, TES unit 220provides a supplemental heat sink that can condense the remaining vaporof the primary fluid. While heat can be rejected to TES unit 220 tocomplete this condensing, TES unit 220 may have a limited thermalcapacity such that only a limited amount of heat can be rejected to TESunit 220. For an intermittent heat load, the thermal capacity of TESunit 220 can be sized to match the difference between the average heatload and the maximum heat load over a designed period of time. After thethermal capacity of the TES unit 220 has been exceeded, TES unit 220must be recharge for subsequent heat loads that exceed the thermaloutput capacity of condenser 208.

Examples of materials that may form TES unit 220 include phase changematerials, chilled water, chilled coolant, two-phase mixtures such aswater and ice, or other suitable material.

TES section 210 may further comprise pressure regulating valve 216,bypass valve 218, pressure regulating valve 222, and bypass valve 224.These components may aid in using TES unit 220 as a heat sink andproviding primary fluid to TES unit 220 at a temperature that rechargesthe thermal capacity of TES unit 220.

During steady-state periods of high heat loads for which the condenser208 is unable to fully condense the primary fluid, bypass valve 218 isopen and bypass valve 224 is shut. Primary fluid flowing through valve218 bypasses pressure regulating valve 216. With bypass valve 224 beingclosed, pressure regulating valve 222 maintains the pressure of theprimary fluid upstream of pressure regulating valve 222 at saturationpressure through both the condenser 208 and TES unit 220. Primary fluidflowing in condenser 208 is partially condensed, and flows throughbypass valve 218 to TES unit 220 that completes the condensing process.TES unit 220 may sub cool the primary fluid. The liquid primary fluid isthen expanded across pressure regulating valve 222, dropping the primaryfluid temperature prior to the fluid returning to heat exchanger 204.

During the transition from the lower heat loads to the above statedsteady state high heat load operation, pressure regulating valve 216will regulate the pressure in condenser 208 and pressure regulatingvalve 222 will regulate pressure in the TES unit 220 independently fromone another. Pressure regulating valve 216 may be fully open when bypassvalve 218 is fully opened. After pressure regulating valve 216 is fullyopen, pressure regulating valve 222 will regulate the pressure in thecondenser 208 and TES unit 220. Bypass valve 224 may be shut during thisoperation. The pressure of the primary fluid in the TES unit 220 may beset to maximize heat rejection, target a specific heat duty, or providea specific amount of sub-cooling at the outlet of TES unit 220. Thepressure within the condenser 208 may be set to maximize condenser heatrejection, keep the compressor 206 operational, or provide a specifiedsub-cool at the outlet of the condenser 208.

During operations in which the condenser 208 is able to fully condense,and possibly sub-cool, the primary fluid, the TES unit may be rechargeat a maximum rate by operating the system such that bypass valve 218 isshut and bypass valve 224 is opened. With valve 218 shut, pressureregulating valve 216 maintains the primary fluid pressure in thecondenser 208 at saturation pressure. The primary fluid is fullycondensed, and possibly sub cooled, by the condenser 208. Primary fluidis expanded across pressure regulating valve 216, dropping thetemperature of the primary fluid as its heat energy is used to vaporizeall or a portion of the primary fluid. The lower temperature primaryfluid flows through TES unit 220, extracting heat from TES unit 220 whenTES unit 220 is at a higher temperature than the primary fluid. Thisheat transfer recharges the thermal capacity of the TES unit. Theprimary fluid mixture then flows through valve 224, bypassing pressureregulating valve 222, on its way to heat exchanger 204 as a vapor or avapor-liquid mixture.

During a transition from operations during which TES unit 220 isrequired to supplement condenser 208 to operations in which the TES unitis recharged at the maximum rate, pressure regulating valve 222 mayregulate the pressure of the TES unit 220 independently of the pressurein condenser 208. Pressure regulating valve 222 may being to open duringthis transition. When pressure regulating valve 222 is fully open bypassvalve 224 is also fully open. Bypass valve 218 is shut for the durationsuch that pressure regulating valve 216 is able to regulate the pressurewithin condenser 208.

Condenser 208 may also be configured to operate in different modes,e.g., with or without forced ventilation. The condenser 208 may be sizedsuch that the average heat load 212 and the compressor 206 power andheat transferred into the primary fluid exceeds the ability of thecondenser 208 to reject heat out 214 during a mode where no forcedventilation is provided. TES unit 220 may provide the additional heatrejection capacity during such a mode of operation.

Pressure regulating valves 216 and 222 may be backpressure regulatingvalves. Bypass valves 218 and 224 may be solenoid valves that areoperated based on the parameters of the primary fluid (e.g., temperatureand pressure, advanced logic control).

Each pressure regulating valve 216 and 222 and its associated bypassvalve 218 and 224, respectively, may be replaced with a single,accurate, fast-acting control valve. For example, the replacement valvefor pressure regulating valve 222 and bypass 224 may be a diaphragm backpressure regulating valve or a pneumatically driven valve. Thisreplacement valve should be able to handle the primary fluid flow in allstates (i.e., vapor, liquid) and accurately control the sub cooling ofthe primary fluid. These features are important if the compressor 206and condenser 208 cannot keep up with the rate of evaporation of the TESunit 220 at low saturation pressures/temperatures (i.e., the temperatureof refrigerant required to cool the TES may not be maintained). By usingdownstream control of the cooling of the primary fluid at the TES unit220, the saturation pressure and temperature of the TES unit 220 can beregulated thereby regulating the heat transfer rate at the TES unit 220without impacting the lower-pressure primary fluid downstream of the TESsection 210.

Embodiments in which a bypass valve is connected in parallel with apressure regulating valve may avoid the pressure drop that may occuracross a fully open pressure regulating valve.

As another example, the replacement valve for pressure regulating valve216 and bypass valve 218 may be a diaphragm-style back-pressureregulating valve, typically pneumatically, spring or electronicallycontrolled valve. This replacement valve should be accurate andfast-acting.

In accordance with some embodiments, a diagram of a heat transfer system400 is provided in FIG. 4. Heat transfer system 400 is comprised of manyof the same components performing the same functions as those describedherein elsewhere. The primary differences between heat transfer systems200 and 400 are located within TES sections 210 and 410. In TES section410, four-way valves 430 and 486 are disposed in TES section 410 tobypass, utilize, or cool TES unit 220 using conduits 484 and 486 as wellas TES cooling fluid conduit 432.

During operations in which the heat load input 212 and compressor 206heat and power input can be accommodated by the heat output 214 ofcondenser 208, four-way valve 430 is positioned to direct the liquid,possibly sub cooled, primary fluid from the effluent of condenser 208 topressure regulating valve 222 via conduit 484 and bypass valve 486. Likeabove, pressure regulating valve 222 maintains the pressure in condenser208 at saturation conditions to ensure that the primary fluid iscondensed and/or sub-cooled in condenser 208. Primary fluid is expandedacross pressure regulating valve 222. A portion of the expanded primaryfluid is directed through TES cooling fluid conduit 432 and bypass valve486 to TES unit 220, thereby providing a supply of chilled primary fluidto cool and recharge TES unit 220. After cooling TES unit 220, the fluidflows through bypass valve 430 to the heat-exchanger-compressor conduit264 via TES cooling fluid conduit 432.

The portion of fluid that does not flow through TES cooling fluidconduit is provided to the inlet 280 of heat exchanger 204 via theTES-section-heat-exchanger conduit 282.

During operations with a heat input 212 plus compressor 206 power andheat input that exceeds the capacity of condenser 208 to fully condensethe primary fluid, four-way valve 430 is positioned to route theeffluent of condenser 208 to TES unit 220 via conduit 486. The TES unit220 completes the condensing and/or sub cooling of the primary fluid.Fluid is then directed to the pressure regulating valve 222 via bypassvalve 486. Pressure regulating valve 222 maintains the upstream primaryfluid pressure at conditions necessary to promote the required heattransfer. The primary fluid is expanded across pressure regulating valve222 and provided back to heat exchanger 204. Four-way valves 430 and/or486 are positioned to prevent the flow of primary fluid in the TEScooling fluid conduit 432 and conduit 484 during this mode of operation.

In some embodiments, TES cooling fluid conduit 432 is connected betweena portion of the TES-section-heat-exchanger conduit 282 and four-wayvalve 486.

While some embodiments described here incorporated a TES section intovapor compression cycle refrigeration system, it should be understoodthat the advantages of incorporating a TES section can be enjoyed inother refrigeration systems, with the TES section supplementing the heatrejecting components of those other systems. As such, nothing hereinshould be construed as limiting the incorporation of a TES section toonly a vapor compression system.

An example of another system is provided for in FIG. 5. FIG. 5illustrate a heat transfer system 500 in accordance with someembodiments. Heat transfer system 500 may comprise similar componentsperforming similar functions as described elsewhere herein. It should beunderstood that many of these components are omitted from FIG. 5 forease of reading.

In addition to components described with respect to other systems, heattransfer system further comprises an accumulator 534 and a pump 536. Theadditional components are combined with the illustrated vaporcompression system to form what is called a liquid overfeed system.Further details and embodiments of liquid overfeed systems are providedfor in the concurrently filed and related U.S. application Ser. No.______ entitled “MECHANICALLY PUMPED SYSTEM FOR DIRECT CONTROL OFTWO-PHASE ISOTHERMAL EVAPORATION”, Docket Number G3106-00290/LWA12265;first named inventor: Eugene Jansen. The entirety of which is herebyincorporated by reference.

Accumulator 534 is located between the effluent of TES section 510(which may be TES section 210 and/or 410) and the suction of compressor206. The accumulator 534 provides several functions, including at leastproviding a surge volume of refrigerant for supply to heat exchanger204, providing pump head for pump 536, and separating the vapor/liquidmixture from the effluent of both the TES section 510 and evaporator204. As such, accumulator 534 has at least two inputs and two outputs.The inputs are from the effluents of the TES section 510 and evaporator204. The two outputs are from vapor supplied to the compressor 206 andthe fluid supplied to pump 536.

For embodiments that utilize a TES cooling fluid conduit 532, theconduit may be placed downstream of pump 536, thereby coupling theoutlet of pump 536 and a valve in the TES section 510, e.g., input offour-way valve 486 of TES section 410. Other locations may also serve asthe initiating point of TES cooling fluid conduit 532.

In accordance with some embodiments, a heat transfer system 600 isillustrated in FIG. 6. Heat transfer system 600 is comprised of many ofthe same components performing the same functions as those describedelsewhere herein. It should be understood that several components ofheat transfer system 600 have been omitted for clarity. The primarydifferences between heat transfer systems 200, 400 and 600 are locatedwithin TES sections 210, 410 and 610. In TES section 610, a four-wayvalve 688 is disposed between the upstream side of both pressureregulating valve 216 and TES unit 220 and the outlet 272 of thecondenser 208. Downstream of both pressure regulating valve 216 and TESunit 220 is pressure regulating valve 222. Unlike heat transfer system200 and 400, pressure regulating valve 216 is not upstream of TES unit220 in system 600. Additionally, TES section 610 comprises a TES unitcooling fluid conduit 932 that is located downstream of pressureregulating valve 222 and fluidically couples this location to an inletof four-way valve 688. For example, TES unit cooling fluid conduit 932may be coupled to the outlet of pump 536 as shown in FIG. 5 such thataccumulator 534 is located within TES-section-heat-exchanger conduit 282between the outlet 278 and the branch-off point of TES unit coolingfluid conduit 932.

During operations in which the heat load input 212 plus compressor 206power and heat input can be accommodated by the heat output 214 ofcondenser 208, four-way valve 688 is positioned to direct the liquid,possibly sub cooled, primary fluid from the effluent of condenser 208 topressure regulating valve 216 via conduit 690. Like above, pressureregulating valve 216 maintains the pressure in condenser 208 atsaturation conditions to ensure that the primary fluid is condensed incondenser 208. Primary fluid is expanded across pressure regulatingvalve 216 and then flows to pressure regulating valve 222, which isfully open and is not maintaining upstream primary fluid pressure. Aportion of the expanded primary fluid may be directed through TEScooling fluid conduit 932 and the four-way valve 688 to TES unit 220,thereby providing a supply of chilled primary fluid to cool and rechargeTES unit 220. A pump, e.g. pump 536, may supply the pump work require todrive the primary fluid through TES cooling fluid conduit 932. Theoutlet 278 of TES section 610 is coupled to the accumulator 534 at apoint upstream of the branch-off of TES cooling fluid conduit 932.

During operations with a heat input 212 that exceeds the capacity ofcondenser 208 to fully condense the primary fluid, four-way valve 688 ispositioned to route the effluent of condenser 208 to TES unit 220 viaconduit 692, bypassing pressure regulating valve 216. The TES unit 220completes the condensing and/or sub cooling of the primary fluid.Pressure regulating valve 222 maintains the upstream primary fluidpressure at conditions necessary to transfer the required heat. Theprimary fluid is expanded across pressure regulating valve 222 andprovided back to heat exchanger 204. Four-way valve 688 is positioned toprevent the flow of primary fluid in the TES cooling fluid conduit 932during this mode of operation.

In accordance with some embodiments, a heat transfer system 700 isillustrated in FIG. 7. System 700 may comprise many of the samecomponents that perform the same functions as described above. System700 differs from those disclosed in that it does not contain a vaporcompression loop. Rather, system 700 is an adsorption system thatcomprises absorber 794, pump 796, generator 798, and valve 7100. Primaryfluid from heat exchanger 204 is provided to absorber 794 wherein theprimary fluid is absorbed into an absorbent while heat is rejected. Theabsorbent/primary fluid mixture is sent via pump 796 to generator 798.In Generator 798, heat is provided to the generator, thereby releasingthe absorbed primary fluid for flow to condenser 208, TES section 210,and then returning to heat exchanger 204. Absorbent is allowed to returnto the absorbed 794 via valve 7100, which also functions to maintain apressure differential between generator 798 and absorber 794.

While the above illustrated system 700 utilizes TES section 210, itshould be understood that this absorption system may also utilize TESsection 410, 510, or 610 and their manner of interfacing with the restof the systems disclosed above.

Although examples are illustrated and described herein, embodiments arenevertheless not limited to the details shown, since variousmodifications and structural changes may be made therein by those ofordinary skill within the scope and range of equivalents of the claims.A person of ordinary skill will recognize that the particular valvesdisclosed herein may be replaced with other, functionally equivalentarrangements. For example, the herein disclosed 4-way valves may bereplaced with combinations of 3-way valves, 2-way valves, or both.

What is claimed is:
 1. A heat transfer system comprising: a primaryfluid; and a primary fluid flow path, said primary fluid disposed insaid primary fluid flow path, said primary fluid flow path comprising: aheat exchanger having an inlet and an outlet, wherein said heatexchanger transfers heat into said primary fluid; a compressor having acompressor inlet and a compressor outlet, wherein said compressor inletis downstream of and coupled to said heat exchanger outlet by aheat-exchanger-compressor conduit; a condenser having a condenser inletand a condenser outlet, wherein said condenser inlet is downstream ofand coupled to said compressor outlet by a compressor-condenser conduit,wherein said condenser transfers heat out of said primary fluid; and athermal energy storage (TES) section, said TES section comprising: aninlet and an outlet, wherein said TES section inlet is downstream of andcoupled to said condenser outlet by a condenser-TES-section conduit, andsaid TES-section outlet is upstream of and coupled to said heatexchanger inlet by a TES-section-heat-exchanger conduit; a TES unithaving an inlet and outlet, wherein said TES unit inlet is downstream ofand coupled to said TES section inlet by a TES-section-TES-unit-inletconduit and said TES unit outlet is upstream of and coupled to said TESSection outlet by a TES-unit-TES-section-outlet conduit; a firstpressure regulating valve downstream of said TES unit; and a secondpressure regulating valve upstream of said first pressure regulatingvalve and downstream of said condenser; a first bypass valve upstream ofsaid TES unit and downstream of said condenser; wherein said secondpressure regulating valve maintains said primary fluid at said condenseroutlet at a first state when the heat transferred into a portion of saidprimary fluid by said heat exchanger is equal to or less than the heattransferred out of said portion of said primary fluid by said condenser,and wherein said first pressure regulating valve maintains said primaryfluid at said TES unit outlet at said first state the heat transferredinto a portion of said primary fluid by said heat exchanger is greaterthan the heat transferred out of said portion of said primary fluid bysaid condenser, and wherein said TES section maintains said primaryfluid at said TES section outlet as a liquid-vapor mixture.
 2. Thesystem of claim 1, wherein said first bypass valve is in parallel withsaid second pressure regulating valve.
 3. The system of claim 2, whereinsaid second pressure regulating valve maintains said primary fluid atsaid TES unit inlet as a liquid-vapor mixture.
 4. The system of claim 2,further comprising: a second bypass valve upstream of said TES unit andcoupled in parallel with said second pressure regulating valve.
 5. Thesystem of claim 1, wherein said second pressure regulating valve isupstream of said TES unit.
 6. A heat transfer system having a closedfluid flowpath comprising in a direction of fluid flow: a heat source; acompressor; a condenser; a first bypass valve in a first mode or a firstpressure regulating valve in a second mode; a thermal energy storage(TES) unit; and a second pressure regulating valve in the first mode ora second bypass valve in the second mode, wherein said TES unit is aheat sink in the first mode and said TES unit is a heat source or heatneutral in a second mode.
 7. The flowpath of claim 6, wherein said firstpressure regulating valve is a diaphragm-style back pressure regulatingvalve.
 8. The flowpath of claim 6, wherein at least one of said firstpressure regulating and said second pressure regulating valve is apneumatically controlled valve.